Numerous noncoding RNAs (ncRNAs) exist in organisms in all three domains of life. In recent years, there has been an explosion in the discovery of novel ncRNAs and their implications in human disease. These ncRNAs are responsible for a remarkable variety of biological functions, including essential roles in the most fundamental aspects of metabolism. In bacteria, ncRNAs perform a diverse array of regulatory functions in controlling genetic signaling and cellular homeostasis. A number of ncRNA classes with extraordinary structural complexity that are among the largest known bacterial ncRNAs have recently been discovered. Of these, OLE (ornate, large, extremophilic) is a conserved, exceptionally structured RNA class that exists almost exclusively in anaerobic extremophiles, including many species of human gut bacteria, human pathogens and organisms with industrial uses. Previous studies have made significant advances toward determining the biological role of the OLE RNA class. However, the function of OLE RNA remains unknown. Therefore, the overall goal of this proposal is to establish its function using several approaches. Specifically, this will be accomplished by (1) identifying the OLE RNA interaction network with crosslinking and co-purification experiments, (2) investigating the cellular localization of OLE RNAs in response to stress with fluorescence microscopy, and (3) applying bioinformatics and biochemical assays to identify ligands for OLE RNAs. Determining the function of this ncRNA class will undoubtedly have an impact on our knowledge about the capabilities of RNA and fundamental aspects of biology, as well as, have potential health-related applications.